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Remediation Technologies Screening Matrix, Version 4.0 4.54 Biofiltration
(Off-Gas Treatment Technology)
  Description Synonyms Applicability Limitations Site Information Points of Contact
Data Needs Performance Cost References Vendor Info. Health & Safety
Table of Contents
Technology>>Air Emissions/Off-Gas Treatment

>>3.14 Air Emissions/Off-Gas Treatment

      >>4.54 Biofiltration
Introduction>> Vapor-phase organic contaminants are pumped through a soil bed and sorb to the soil surface where they are degraded by microorganisms in the soil.


Figure 4-54: Typical Methanotrophic Biofilm Reactor Diagram  

Biofiltration is a low-cost and highly effective air pollution control (APC) technology  in which vapor-phase organic contaminants are passed through a bed of porous media and sorb to the media surface where they are degraded by microorganisms in the media. Specific strains of bacteria may be introduced into the filter and optimal conditions provided to preferentially degrade specific compounds. The biofilter provides several advantages over conventional activated carbon adsorbers. First, bio-regeneration keeps the maximum adsorption capacity available constantly; thus, the mass transfer zone remains stationary and relatively short. The filter does not require regeneration, and the required bed length is greatly reduced. These features reduce capital and operating expenses. Additionally, the contaminants are destroyed not just separated, as with granulated activated carbon (GAC) technologies.

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As with other biological treatment processes, biofiltration is highly dependent upon the biodegradability of the contaminants. Under proper conditions, biofilters can remove virtually all selected contaminants to harmless products. Biofiltration is used primarily to treat nonhalogenated VOCs and fuel hydrocarbons. Halogenated VOCs also can be treated, but the process may be less effective. Biofilters have been successfully used to control odors from compost piles.

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The following factors may limit the applicability and effectiveness of the process:
  • The rate of influent air flow is constrained by the size of the biofilter.
  • Fugitive fungi may be a problem.
  • Low temperatures may slow or stop removal unless the biofilter is climate-controlled.
  • Compounds that are recalcitrant to biodegratation will not be converted to harmless products.

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Data Needs:

A detailed discussion of these data elements is provided in Subsection 2.2.3. (Data Requirements for Air Emissions/Off-Gases).

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Performance Data:

Nonproprietary filters that require low air loading rates for organics (100 ppm) have been used successfully for more than 20 years. Proprietary designs that support higher air loadings also are available. Biofilters have been used extensively in Europe and Japan, but only recently have they received attention in the United States.

Moisture levels, pH, temperature, and other filter conditions may have to be monitored to maintain high removal efficiencies. Filter flooding and plugging as a result of excessive biomass accumulation may require periodic mechanical cleaning of the filter.

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Cost estimates range from $5 to $10 per kilogram of contaminant ($2.27 to $4.54 per pound).

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USAEC, 1997. "Remediation of Air Streams Contaminated with Trichloroethylene Using Biofiltration at Anniston Army Depot" in Innovative Technology Demonstration, Evaluation and Transfer Activities, FY 96 Annual Report, Report No. SFIM-AEC-ET-CR-97013, pp. 19-20.

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Site Information:

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Points of Contact:

General FRTR Agency Contacts

Technology Specific Web Sites:

Government Web Sites

Non Government Web Sites

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Vendor Information:

A list of vendors offering Air Emission/Off-Gas Treatment is available from  EPA REACH IT which combines information from three established EPA databases, the Vendor Information System for Innovative Treatment Technologies (VISITT), the Vendor Field Analytical and Characterization Technologies System (Vendor FACTS), and the Innovative Treatment Technologies (ITT), to give users access to comprehensive information about treatment and characterization technologies and their applications.

Government Disclaimer

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Health and Safety:

Hazard Analysis

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Introduction Contaminants Treatments/Profiles References Appendices Navigation